Bioequivalence of vildagliptin/metformin fixed-dose combination tablets and a free combination of vildagliptin and metformin in healthy subjects

OBJECTIVE: To assess the bioequivalence of vildagliptin/metformin fixed-dose combination tablets (at doses of 50/500, 50/850 and 50/1,000 mg) with free combination of the individual drugs in healthy subjects. METHODS: The pharmacokinetics of vildagliptin and metformin following administration of a fixed-dose combination tablet of vildagliptin/metformin at doses of 50/500 mg (Study I), 50/850 mg (Study II) and 50/1,000 mg (Study III) compared with administration of the individual drugs as free combinations were investigated. All three studies were open-label, single-center, randomized, two-period, two-treatment crossover studies in healthy subjects. RESULTS: Pharmacokinetic parameters (AUC(0-infinity), C(max), t(max), t(1/2) and CL/F) for vildagliptin and metformin across the three studies were similar whether vildagliptin and metformin were administered as a single fixed-dose combination tablet (vildagliptin/metformin 50/500, 50/850 or 50/1,000 mg) or as the respective individual tablets. The point estimates and 90% CI of the geometric mean ratios for vildagliptin and metformin C(max), AUC(0-t), and AUC(0-infinity) were all within the predefined bioequivalence range of 0.80 - 1.25. Administration of the vildagliptin/metformin combination tablets was well tolerated; the incidence of adverse events was similar to that observed with the respective free combinations of vildagliptin and metformin, and the most common individual adverse events were mild gastrointestinal events, which are commonly observed with metformin treatment. CONCLUSIONS: The fixed-dose combination tablet of vildagliptin/metformin is bioequivalent to administration of the individual drugs as a free combination at dose levels of 50/500, 50/850 and 50/1,000 mg and is well tolerated. Consequently, the fixed-dose combination tablets are considered therapeutically equivalent and exchangeable to the free combination in clinical practice. Furthermore, the fixed-dose combination tablets are expected to enhance convenience and thereby improve compliance and improve glycemic control for patients with Type 2 diabetes on both medications.     

Oral antidiabetic drugs: bioavailability assessment of fixed-dose combination tablets of pioglitazone and metformin. Effect of body weight, gender, and race on systemic exposures of each drug

Bioavailability of pioglitazone and metformin, in 2 dose strengths, given either as a fixed-dose combination tablet or as coadministration of commercial tablets (coad), was studied in young healthy subjects in 2 separate studies. In study I (n = 63), single oral doses of 15-mg pioglitazone/500-mg metformin fixed-dose combination tablets or equivalent doses of commercial tablets were administered, in a fasting state, in an open-label, randomized, crossover study with a 7-day washout period between treatments. Study II (n = 61) was similar in design to study I, except the 15/850-mg fixed-dose combination tablet and coad treatments were evaluated. Least squares mean (fixed-dose combination/coad) ratios and 90% confidence intervals of the ratios for the 15/500-mg dose strength for the maximum observed serum concentration (Cmax) and area under the serum concentration-time curve from time 0 to infinity (AUC(infinity)) were 0.95 (0.86-1.05) and 1.02 (0.98-1.08), respectively, for pioglitazone and 0.99 (0.95-1.03) and 1.03 (0.98-1.08), respectively, for metformin. Bioequivalency for pioglitazone and metformin between fixed-dose combination tablets and coad treatments was met for both strengths of fixed-dose combination tablets. In a post hoc meta-analysis of combined data from the 2 studies (n = 124), there was considerable overlapping in AUC(infinity) values between gender and race (Caucasians, Blacks, and Hispanics), making neither gender- nor racial-based dosing of pioglitazone or metformin necessary.     

Pharmacokinetics and pharmacodynamics of glyburide/metformin tablets (Glucovance) versus equivalent doses of glyburide and metformin in patients with type 2 diabetes

OBJECTIVE: To compare the effects of two different formulations of glibenclamide (glyburide) combined with metformin on postprandial glucose excursions, and to assess their pharmacokinetics. The formulations were a combination glibenclamide/metformin tablet (Glucovance; controlled-particle-size glibenclamide and metformin) versus glibenclamide (Micronase) and metformin (Glucophage) coadministered separately. DESIGN: A randomised, double-blind, two-way crossover study in which patients with type 2 diabetes received either glibenclamide/metformin 2.5/500mg tablets or glibenclamide 2.5mg with metformin 500mg twice daily for 14 days. After a 2-week washout, patients were crossed over to the other treatment for 14 days. Patients consumed standardised meals on the days when pharmacokinetic and pharmacodynamic evaluations were performed. PARTICIPANTS: Forty patients with type 2 diabetes were enrolled; 37 were randomised (18 men, 19 women) and 35 completed the study. Mean age was 58 years; mean body mass index was 31 kg/m(2). The baseline glycated haemoglobin (HbA(1c)) was 9.3% for both treatment groups. MAIN OUTCOME MEASURE: Two-hour postprandial glucose excursion (PPGE) was used to assess postprandial glucose dynamics. RESULTS: Treatment with glibenclamide/metformin resulted in a significantly smaller mean PPGE than was attained by treatment with glibenclamide plus metformin, according to measurements taken after the day 14 afternoon standardised meal (89.5 vs 117.4 mg/dl, p = 0.011). The mean glibenclamide peak concentration (C(max)) was significantly greater (approximately 16%) after glibenclamide/metformin treatment on both days 1 and 14. Glibenclamide/metformin treatment was associated with a 2-fold greater area under the concentration-time curve to 3 hours for glibenclamide (AUC(3)) [p < 0.001], although the AUC over the administration interval was equivalent for both formulations. CONCLUSION: In patients with type 2 diabetes, glibenclamide/metformin resulted in lower PPGE, suggesting that the higher glibenclamide AUC(3) observed with this formulation may contribute to better postprandial glycaemic control than is attained by glibenclamide plus metformin separately.     

高效液相色谱-串联质谱法同时测定人血浆中瑞格列奈和二甲双胍及其在人体药动学中的应用

目的:建立高效液相色谱-串联质谱法(HPLC-MS/MS)同时测定人血浆中瑞格列奈和二甲双胍浓度的方法,并进行人体药动学研究。方法:以乙腈沉淀蛋白处理血浆样品,替米沙坦做内标,采用Kromasil 60-5CN色谱柱(2.1 mm×100 mm, 5 μm),流动相为20 mmol·L^-1醋酸铵水溶液(含0.2%甲酸)-乙腈(45:55);质谱采用电喷雾离子化-多反应离子监测(ESI-MRM)。并测定12名健康志愿者单剂量口服瑞格列奈盐酸二甲双胍复方片(2 mg:500 mg)后瑞格列奈和二甲双胍的血浆浓度。结果:瑞格列奈和二甲双胍分别在0.05~50 μg·L^-1、2~2 000 μg·L^-1范围内线性良好,定量下限分别为0.05 μg·L^-1和2 μg·L^-1,日内日间精密度均小于8%,提取回收率分别为77.32%~80.65%和78.98%~82.46%。瑞格列奈和二甲双胍的主要药动学参数C_max分别为(29.50±9.57),(1 167±197.77)μg·L^-1;t_max分别为(0.83±0.39),(1.88±0.64)h;t_1/2分别为(1.11±0.38),(4.31±0.86)h;AUC_0→∞分别为(56.90±20.31),(7 407.32±1 653.25)μg·L^-1·h^-1。结论:建立的分析方法灵敏、准确可靠,样品处理快速、简便,适用于瑞格列奈/盐酸二甲双胍复方片人体药动学和生物等效性研究。     

盐酸二甲双胍/格列本脲复方片剂在人体的药代动力学

目的　建立人血浆中格列本脲的HPLC ESI MS测定法 ,研究志愿者口服格列本脲与二甲双胍的复方片剂后的药代动力学行为。方法　人血浆样品中格列本脲的测定方法 :血浆样品以 1mol·L- 1的盐酸酸化后用乙酸乙酯提取 ,进行HPLC ESI MS分析 ,色谱柱为LichrospherC18(dp 5μm ,4 6mmID× 2 5cm ) ,流动相为甲醇 -10mmol·L- 1醋酸铵水溶液 (78∶2 2 ,V/V) ,检测方式为SIM方式 ,检测离子为m/z 492 1(格列本脲 )、m /z 444 1(内标 )。 2 0名健康志愿者交叉口服供试片和参比片 ,剂量均为格列本脲 2 5mg和盐酸二甲双胍 50 0mg。 结果　在 0 3 10～ 413 μg·L- 1范围内格列本脲峰面积与内标峰面积的比值与浓度的线性关系良好。格列本脲受试制剂与参比制剂的T1/2 分别为(5 4± 0 8)h、(5 9± 1 0 )h ,Cmax 分别为 (14 6± 2 2 ) μg·L- 1、(12 3± 16) μg·L- 1,Tmax分别为 (2 7± 0 9)h、(3 0±0 7)h ,AUC0～ 3 6 分别为 (73 0± 14 0 ) μg·h·L- 1、(63 2± 117)μg·h·L- 1;二甲双胍受试制剂与参比制剂的T1/2 分别为(3 0± 0 6)h、(3 0± 0 4)h ,Cmax分别为 (1 61± 0 3 2 )mg·L- 1、(1 62± 0 3 3 )mg·L- 1,Tmax分别为 (1 8± 0 2 )h、(1 7± 0 4)h ,AUC0～ 15 分别为 (7 3 7± 1 3 4 )     

Randomized study of repaglinide alone and in combination with metformin in Chinese subjects with type 2 diabetes naive to oral antidiabetes therapy

Objective: The aim of this research is to determine efficacy and safety of repaglinide alone and in combination with metformin in Chinese subjects with type 2 diabetes naive to oral antidiabetes therapy.

Methods: A 16-week, open-label, randomized, active-controlled, parallel-group trial was carried out. Subjects were randomized (1:1) to repaglinide 1 mg t.i.d. (maximum dose, 4 mg t.i.d.) or repaglinide plus metformin 1 mg/500 mg t.i.d. (maximum dose, 4 mg/500 mg t.i.d.). Eligible subjects (18 – 75 years old) had type 2 diabetes, A1C > 8.5%, BMI ≤ 35 kg/m², and were naive to oral antidiabetes agents.

Results: The primary outcome was A1C reduction. Secondary end points included fasting plasma glucose (FPG), 2-h postprandial glucose (PPG), and 7-point plasma glucose. Baseline characteristics (repaglinide/metformin, n = 218; repaglinide-only, n = 214) were similar between groups. Mean A1C reduction (± SD) was 4.51 ± 1.64% (combination) and 4.05 ± 1.59% (monotherapy). Estimated mean treatment difference for repaglinide/metformin versus repaglinide-only was -0.30% (95% CI -0.49 to -0.11; p < 0.01). Combination treatment demonstrated significant improvements versus monotherapy in FPG, 7-point plasma glucose, and lunchtime and dinnertime 2-h PPG (all p < 0.05). Hypoglycemia rates were 2.04 (combination) versus 1.35 (monotherapy) events/subject-year (p = 0.058). Adverse events were comparable between groups.

Conclusions: Repaglinide plus metformin and repaglinide alone provided significant improvements in glycemic control and were well tolerated in Chinese patients naive to treatment with oral antidiabetes agents. Combination therapy with repaglinide plus metformin showed superiority to repaglinide monotherapy in this population. Limitations of this study are that subjects were newly diagnosed and had high mean baseline A1C, which may affect generalizability of results.     

Metformin extended release--DepoMed: metformin, metformin gastric retention, metformin GR

Metformin extended release [Glumetza, metformin hydrochloride, metformin gastric retention, metformin GR] is a proprietary once-a-day formulation of metformin hydrochloride under development with DepoMed for the treatment of diabetes. In May 2002, DepoMed licensed manufacturing and marketing rights for its proprietary formulation of metformin extended release (500mg dose) to Biovail Corporation for the US (including Puerto Rico) and Canada. Under the terms of the agreement, Biovail would pay a $25 million milestone fee upon approval and also customary royalties on the net sales in the US and Canada. Biovail also agreed to acquire approximately 2.4 million of additionally issued DepoMed shares for $12.3 million. Biovail has subsequently developed a 1000mg dose of metformin extended release. In April 2004, Depomed and Biovail amended their original license agreement of May 2002. Under the terms of the amended agreement, Depomed will receive royalties on sales of Biovail's 1000mg tablet in the US and Canada. In turn, Biovail acquired access to Depomed's clinical data for the metformin 500mg tablet that will be used to accelerate regulatory filings for Biovail's 1000mg tablet and establish equivalence between the two dosages. Metformin GR is available for partnership in Europe and Asia (Bio-Square-2004, Basel, Switzerland). In April 2004, Depomed and Biovail filed an NDA with the US FDA for the once-daily, extended-release formulation of metformin extended release (Glumetza), 500mg and 1000mg tablets. The 500mg dosage was developed by Depomed using its patented drug delivery GR technology, while Biovail developed the metformin 1000mg dose using its proprietary Smartcoat delivery technology. Depomed completed two double-blind, pivotal, phase III clinical trials with metformin extended release 500mg at 60 sites in the US in more than 1000 patients with type 2 diabetes. In three different dosing regimens, metformin extended release significantly decreased the glycosylated haemoglobin level similarly to that of metformin immediate release. Biovail successfully compared the metformin extended release 1000mg dose with Depomed's 500mg dose in multiple equivalence studies. In these studies, metformin extended release was well tolerated and demonstrated an excellent safety profile in terms of gastrointestinal adverse events. The licensee, Biovail, has submitted an application for metformin extended release with Health Canada. Bristol-Myers Squibb is marketing a proprietary, once-daily extended-release formulation of metformin (Glucophage XR). Several companies are developing controlled-release and extended release formulations of metformin.     

盐酸二甲双胍片在中国健康人体的生物等效性

目的评价2种国产盐酸二甲双胍片(口服降糖药)在中国健康人体的生物等效性。方法 20名健康男性受试者随机交叉单剂量口服盐酸二甲双胍片试验药物和对照药物,各1.0 g。用高效液相色谱法测定血浆中盐酸二甲双胍的浓度,用DAS 2.0软件计算药代动力学参数,并对2种药物进行生物等效性评价。结果试验药物和对照药物的主要药代动力学参数如下:Cmax为(2.83±0.53),(2.57±0.57)mg.L-1;Tmax为(1.55±0.39),(1.63±0.36)h;t1/2为(3.70±1.76),(3.36±0.72)h;AUC0-24为(10.20±1.95),(9.71±2.56)mg.h.L-1。AUC0-24、AUC0-∞、Cmax的90%可信区间分别为99.1%～114.6%、99.1%～113.8%和100.6%～110.4%。试验药物相对于对照药物的生物利用度F为(108.3±20.5)%。结论试验药物和对照药物生物等效。     

Bioavailability of amlodipine besylate/atorvastatin calcium combination tablet

The bioequivalence of combination tablets containing amlodipine besylate/atorvastatin calcium with coadministered matching doses of amlodipine besylate and atorvastatin calcium tablets was investigated in randomized, 2-way crossover studies in healthy volunteers (N = 126). Subjects received a single dose of the amlodipine/atorvastatin tablet or coadministered matching doses of amlodipine and atorvastatin at the highest (10/80 mg; n = 62) and lowest (5/10 mg; n = 64) dose strengths. Atorvastatin geometric mean ratios for maximum plasma concentration (C(max)) and area under the plasma concentration-time curve (AUC) for the highest and lowest dose strengths were 94.1 and 98.8, and 104.5 and 103.8, respectively. Amlodipine geometric mean ratios for C(max) and AUC for the highest and lowest dose strengths were 100.8 and 103.4, and 100 and 102.7, respectively. The 90% confidence intervals for all comparisons were within 80% to 125%, demonstrating bioequivalence for amlodipine and atorvastatin at both dose strengths. Use of amlodipine/atorvastatin combination tablets may provide a more integrated approach to treatment of cardiovascular risk.     

Metformin extended release: metformin gastric retention, metformin GR, metformin XR

Metformin extended release [Glumetza, metformin hydrochloride, metformin gastric retention, metformin GR] is a proprietary once-a-day formulation of metformin hydrochloride under development with Depomed for the treatment of diabetes mellitus. In May 2002, Depomed licensed manufacturing and marketing rights for its proprietary formulation of metformin extended release (500mg dose) to Biovail Corporation for the US (including Puerto Rico) and Canada. Under the terms of the agreement, Biovail will pay DepoMed a 25 million dollars milestone fee upon approval of the 500mg dosage and also customary royalties on the net sales in the US and Canada. Biovail also agreed to acquire approximately 2.4 million of additionally issued Depomed shares for 12.3 million dollars. Biovail has subsequently developed a 1000mg dose of metformin extended release [metformin XR] using its proprietary Smartcoat delivery technology allowing a graduated release of the active drug from the tablet. In April 2004, Depomed and Biovail amended their original license agreement of May 2002. Under the terms of the amended agreement, Depomed will receive royalties on sales of Biovail's 1000mg tablet in the US and Canada. In turn, Biovail acquired access to Depomed's clinical data for the metformin 500mg tablet that will be used to accelerate regulatory filings for Biovail's 1000mg tablet and establish equivalence between the two dosages. Biovail is seeking marketing partners for metformin extended release (Glumetza) in the US. The company anticipates signing an agreement for the US during the second half of 2005. In Canada, Biovail Corporation will market Glumetzatrade mark through its Canadian division, Bioval Pharmaceuticals Canada. Depomed has an agreement with LG Life Sciences for the commercialisation and distribution of metformin extended release in Korea. Metformin GR is available for partnership in Europe and Asia. Biovail Corporation and Depomed announced in June 2005 that the US FDA has approved metformin extended release (Glumetza) 500mg and 1000mg tablets for the treatment of type 2 diabetes mellitus. Biovail plans launching the product in the fourth quarter of 2005. In July 2005, Biovail paid Depomed a 25 million dollars milestone payment following approval of metformin extended release in the US for type 2 diabetes. In March 2005, Biovail Corporation and Depomed announced that they have received an approvable letter from the FDA for the once-daily, extended-release formulation of metformin extended release (Glumetza) 500mg and 1000mg tablets. The letter specified an issue related to finalising one manufacturing specification. There were no clinical labeling issues identified in the letter. Both companies filed a response to a specified issue at the FDA on 8 April 2005. The companies believed that the response will be classified as a Class I response with a 60-day review period. The 500mg dosage was developed by Depomed using its patented drug delivery GR technology, while Biovail developed metformin 1000mg dose using its proprietary Smartcoat delivery technology. Biovail's NDA for a once-daily, extended-release formulation of metformin HCl for the treatment of type II diabetes was filed in April 2004 and accepted for review in June 2004 by the FDA. Depomed completed two double-blind, pivotal, phase III clinical trials with metformin extended release 500mg at 60 sites in the US in more than 1000 patients with type 2 diabetes. In three different dosing regimens, metformin extended release significantly decreased the glycosylated haemoglobin level similarly to that of metformin immediate-release. Biovail successfully compared metformin extended release 1000mg dose with Depomed's 500mg dose in multiple equivalence studies. In these studies, metformin extended release was well tolerated and demonstrated an excellent safety profile in terms of gastrointestinal adverse events. On 1 June 2005, Depomed and Biovail Comporation, the licensee, announced that the Therapeutic Products Directorate in Canada issued a Notice of Compliance for metformin extended release (Glumetza) 500mg and 1000mg for the treatment of type 2 diabetes. Biovail Pharmaceuticals Canada plans to launch the product in the fourth quarter of 2005. Biovail has submitted an application for metformin extended release with the Therapeutic Products Directorate in Canada. and received notification of acceptance for review in August 2004. Bristol-Myers Squibb is marketing a proprietary, once-daily extended-release formulation of metformin (Glucophage XR). Several companies are developing controlled-release and extended-release formulations of metformin.     

Pioglitazone/metformin

A fixed-dose pioglitazone/metformin tablet is approved in the US and the EU for the treatment of adult patients with type 2 diabetes mellitus who currently have inadequate glycaemic control with metformin monotherapy. In the US, the combination tablet is also approved for the treatment of adult patients with type 2 diabetes who currently have inadequate glycaemic control with pioglitazone monotherapy and for those already receiving a combination of pioglitazone and metformin. Bioequivalence, based on absorption and bioavailability parameters, has been established between the fixed-dose tablets and equivalent doses of pioglitazone and metformin coadministered as separate agents. Combination therapy with pioglitazone plus metformin was significantly more effective at improving both glycaemic and lipid control than metformin plus placebo in patients with type 2 diabetes in a 16-week, well designed trial. Pioglitazone plus metformin demonstrated similar antihyperglycaemic efficacy to that of rosiglitazone plus metformin in a well designed 12-month trial; however, pioglitazone plus metformin was the superior combination in terms of lipid control. In several comparative trials of 1-3.5 years' duration, pioglitazone plus metformin was at least as effective as combination therapy with a sulphonylurea plus metformin in terms of antihyperglycaemic efficacy, but provided superior lipidaemic control with regard to levels of triglyceride and high-density lipoprotein-cholesterol. Pioglitazone plus metformin was generally well tolerated in patients with type 2 diabetes, with adverse events common to metformin monotherapy observed at a similar incidence to that with metformin plus placebo.     

Comparative bioavailability of rifampicin, isoniazid and pyrazinamide from a four drug fixed dose combination with separate formulations at the same dose levels

Fixed dose combination (FDC) formulations became popular in the treatment of tuberculosis (TB) because of the better patient compliance, reduced risk of monotherapy and emergence of drug resistance in contrast to treatment with separate formulations of two to four first-line drugs. However, its successful implementation in national programs is limited by probable bioinequivalency of rifampicin if present in FDC form. In this regard, World Health Organization (WHO) and International Union Against Tuberculosis and Lung Disease (IUATLD) recommend FDCs only of proven bioavailability. Hence, bioequivalence study of four drug FDC tablet was conducted using 22 healthy male volunteers according to WHO recommended protocol to determine bioavailability of rifampicin, isoniazid and pyrazinamide compared to standard separate combination at the same dose level. The study was designed as two period, two treatment crossover experiment with a washout period of 1 week. Bioequivalence of rifampicin was estimated by plasma and urinary method for both rifampicin and its active metabolite, des-acetyl rifampicin whereas isoniazid and pyrazinamide were estimated from plasma. Mean concentration time profiles and all the pharmacokinetic parameters of rifampicin, isoniazid and pyrazinamide from FDC tablet were comparable to individual formulations and passed the bioequivalence test with power of the test above 95%. Further, bioequivalence of both rifampicin and isoniazid shows that in vitro interaction of rifampicin and isoniazid is clinically insignificant. Thus, it was concluded that FDC formulation is bioequivalent for rifampicin, isoniazid and pyrazinamide and ensures the successful treatment of TB without compromising therapeutic efficacy of any of these components of anti-TB therapy.     

Steady-state pharmacokinetics of a novel extended-release metformin formulation

BACKGROUND AND OBJECTIVE: Metformin is an effective treatment for type 2 diabetes mellitus. The pharmacokinetic characteristics of the conventional immediate-release (IR) formulation of metformin (Glucophage), however, necessitate two- or three-times-daily dosing. Development of a novel extended-release (XR) formulation of metformin (Glucophage XR) using GelShield Diffusion System technology provides a once-daily dosing option. The objective of this study was to assess the steady-state pharmacokinetics of metformin XR tablets. STUDY DESIGN: This was an open-label, multiple-dose, five-regimen, two-sequence clinical study lasting 5 weeks. METHODS: Subjects were 16 healthy volunteers aged 18-40 years. Three 1-week regimens of metformin XR (500, 1000 and 1500 mg once daily) were administered sequentially. Subjects were alternately given either metformin XR 2000 mg once daily or metformin IR 1000 mg twice daily during weeks 4 and 5. The pharmacokinetic properties of metformin XR were assessed on two separate days at steady state and compared with those of metformin IR. RESULTS: Absorption of metformin XR was slower than that of metformin IR (time to maximum plasma concentration = 7 versus 3 hours). Maximum plasma concentrations (Cmax) following the administration of metformin XR 2000 mg once daily was 36% higher than that following the evening dose of metformin IR 1000 mg twice daily. The extent of absorption, determined by area under the plasma concentration-time curve (AUC), was equivalent for both formulations. The mean accumulation ratio of metformin XR was 1.0, indicating no accumulation with multiple-dose administration. Intrasubject variabilities in Cmax and AUC of metformin were comparable between metformin XR and metformin IR. This novel formulation of metformin XR was well tolerated at single doses up to 2000 mg once daily for 7 days, and adverse events were similar to those reported with metformin IR. CONCLUSION: The pharmacokinetic parameters of metformin XR tablet using GelShield Diffusion System technology were similar to those of metformin IR. Metformin XR was well tolerated at single doses up to 2000 mg once daily.     

Oral antidiabetic drugs: effect of food on absorption of pioglitazone and metformin from a fixed-dose combination tablet

An open-label, randomized, crossover study involving 28 healthy subjects was conducted to compare the peak (Cmax) and total (AUC(lqc), AUC(infinity)) exposures to pioglitazone and metformin after single-dose administration of a fixed-dose combination tablet containing 15 mg of pioglitazone plus 850 mg metformin when given under fasted versus fed states, with a washout period of 7 days between treatments. Two different fixed-dose combination formulations (bilayer and pioglitazone-micronized fixed-dose combination tablets) were tested. The pioglitazone-micronized fixed-dose combination formulation was selected for clinical development and regulatory approval; the present study describes food effect results with this formulation. For pioglitazone, least squares mean ratios (fed/fasted) and the 90% confidence intervals of these ratios were 1.05 (0.93-1.18) for Cmax, 1.13 (1.02-1.25) for AUC(lqc), and 1.11 (1.01-1.22) for AUC(infinity). For metformin, these values were 0.72 (0.65-0.79) for Cmax, 0.87 (0.81-0.94) for AUC(lqc), and 0.87 (0.81-0.94) for AUC(infinity). Dosing with food resulted in median prolongation of tmax values by 1.5 hours for metformin and 2.0 hours for pioglitazone. Because bioequivalency criteria were met (fed/fasted 90% confidence interval between 0.80 and 1.25) for both pioglitazone and metformin AUC, fixed-dose combination tablets can be taken with or without food, but to minimize gastrointestinal adverse effects of metformin, the fixed-dose combination tablets are recommended to be taken with food.     

Bioequivalence of an ezetimibe/simvastatin combination tablet and coadministration of ezetimibe and simvastatin as separate tablets in healthy subjects

OBJECTIVE: To assess the bioequivalence of an ezetimibe/simvastatin (EZE/SIMVA) combination tablet compared to the coadministration of ezetimibe and simvastatin as separate tablets (EZE + SIMVA). METHODS: In this open-label, randomized, 2-part, 2-period crossover study, 96 healthy subjects were randomly assigned to participate in each part of the study (Part I or II), with each part consisting of 2 single-dose treatment periods separated by a 14-day washout. Part I consisted of Treatments A (EZE 10 mg + SIMVA 10 mg) and B (EZE/SIMVA 10/10 mg/mg) and Part II consisted of Treatments C (EZE 10 mg + SIMVA 80 mg) and D (EZE/SIMVA 10/80 mg/mg). Blood samples were collected up to 96 hours post-dose for determination of ezetimibe, total ezetimibe (ezetimibe + ezetimibe glucuronide), simvastatin and simvastatin acid (the most prevalent active metabolite of simvastatin) concentrations. Ezetimibe and simvastatin acid AUC(0-last) were predefined as primary endpoints and ezetimibe and simvastatin acid Cmax were secondary endpoints. Bioequivalence was achieved if 90% confidence intervals (CI) for the geometric mean ratios (GMR) (single tablet/coadministration) of AUC(0-last) and Cmax fell within prespecified bounds of (0.80, 1.25). RESULTS: The GMRs of the AUC(0-last) and Cmax for ezetimibe and simvastatin acid fell within the bioequivalence limits (0.80, 1.25). EZE/ SIMVA and EZE + SIMVA were generally well tolerated. CONCLUSIONS: The lowest and highest dosage strengths of EZE/SIMVA tablet were bioequivalent to the individual drug components administered together. Given the exact weight multiples of the EZE/SIMVA tablet and linear pharmacokinetics of simvastatin across the marketed dose range, bioequivalence of the intermediate tablet strengths (EZE/SIMVA 10/20 mg/mg and EZE/SIMVA 10/40 mg/mg) was inferred, although these dosages were not tested directly. These results indicate that the safety and efficacy profile of EZE + SIMVA coadministration therapy can be applied to treatment with the EZE/SIMVA tablet across the clinical dose range.     

Biowaiver extension potential to BCS Class III high solubility-low permeability drugs: bridging evidence for metformin immediate-release tablet.

The biopharmaceutics classification system (BCS) allows biowaiver for rapid dissolving immediate-release (IR) products of Class I drugs (high solubility and high permeability). The possibility of extending biowaivers to Class III high solubility and low permeability drugs is currently under scrutiny. In vivo bioequivalence data of different formulations of Class III drugs would support such an extension. The objective of this work was to demonstrate the bioequivalence of two marketed IR tablet products of a Class III drug, metformin hydrochloride, that are rapidly dissolving and have similar in vitro dissolution profiles. The effect of race on the systemic exposure of metformin was also explored. A randomized, open-label, two-period crossover study was conducted in 12 healthy Chinese male volunteers. Each subject received a single-dose of 500 mg of each product after an overnight fasting. The plasma concentrations of metformin were followed for 24 h. No significant formulation effect was found for the bioequivalence metrics: areas under concentration-time curve (AUC0-t, AUC0-infinity) and maximal concentration (Cmax). The 90% confidence intervals for the ratio of means were found within the acceptance range of 80-125% for the log-transformed data. Based on these results, it was concluded that the two IR products are bioequivalent. The pharmacokinetic parameters of metformin in Chinese for both products were similar and were in good agreement with those reported for metformin IR tablets in other ethnic populations. This study serves as an example for supporting biowaiver for BCS Class III drugs.     

瑞格列奈分散片在健康人体中的相对生物利用度研究

目的研究瑞格列奈分散片与瑞格列奈片在中国男性健康志愿者体内的相对生物利用度。方法采用随机双周期自身交叉对照试验设计,20名健康男性受试者分别口服受试制剂瑞格列奈分散片和参比制剂瑞格列奈片4mg,采用LC-MS／MS法测定给药后不同时间瑞格列奈的血药浓度。利用DAS2．0计算药动学参数和进行统计分析,通过方差分析和双单侧t检验及90％置信区间法进行生物等效性评价。结果受试制剂与参比制剂中瑞格列奈的Cmax分别为（110．8±59．9）、（101．5±48．8）μg·L^-1;tmax分别为（0．54±0．20）和（0．65±0．34）h;AUC0～8分别为（112．5±38．4）和（110．8±42．O）μg·h·L^-1;AUC0-∞分别为（114．1±38．8）和（112．7±41.8）μg·h·L^-1。受试制剂对参比制剂的相对生物利用度F（以AUC0-8作为评价依据）为（105．0±25．0）％。结论受试制剂与参比制剂具有生物等效性。     

Lack of bioequivalence between different formulations of isosorbide dinitrate and hydralazine and the fixed-dose combination of isosorbide dinitrate/hydralazine: the V-HeFT paradox

OBJECTIVE: To investigate whether the apparent discrepancy between the efficacy of the combination of isosorbide dinitrate (ISDN) and hydralazine demonstrated in the first V-HeFT trial (V-HeFT I) and that in V-HeFT II could be explained by pharmacokinetic differences in the study drug formulations, and to compare the pharmacokinetic profile of the fixed-dose combination of ISDN/hydralazine (FDC ISDN/HYD; BiDil) formulation used in A-HeFT with that of the V-HeFT study drug formulations. STUDY PARTICIPANTS AND METHODS: A bioequivalence study was performed (n = 18-19 per group) comparing the ISDN and hydralazine formulations used in V-HeFT I, V-HeFT II and A-HeFT in healthy volunteer men and women aged 18-40 years. In phase A of the study, subjects received a reference solution of hydralazine hydrochloride/ISDN (37.5mg/10mg) orally. Slow acetylators were identified and randomised into three groups in phase B to receive a single oral dose of identical amounts of hydralazine hydrochloride/ISDN (37.5mg/10mg) from either (i) a hydralazine capsule plus an ISDN tablet (the V-HeFT I formulation); (ii) a hydralazine tablet plus an ISDN tablet (the V-HeFT II formulation); or (iii) FDC ISDN/HYD (the A-HeFT formulation). Blood/plasma concentrations of hydralazine and ISDN were determined from the blood samples taken between 0 and 36 hours. RESULTS: In phase B, the maximum observed concentrations (C(max)) were 65.9 +/- 53.9, 28.2 +/- 15.8 and 51.5 +/- 54.3 ng/mL of unchanged hydralazine, and 23.1 +/- 12.3, 21.7 +/- 13.4 and 26.7 +/- 18.7 ng/mL of ISDN for the V-HeFT I, V-HeFT II and A-HeFT formulations, respectively. The area under the blood/plasma concentration-time curve (AUC) values were 32.6 +/- 13.4, 23.3 +/- 15.1 and 32.6 +/- 18.5 ng x h/mL of hydralazine, and 24.4 +/- 9.0, 24.8 +/- 8.0 and 23.5 +/- 6.3 ng x h/mL of ISDN for the V-HeFT I, V-HeFT II and A-HeFT formulations, respectively. For comparison of bioequivalence, the C(max) and AUC were normalised to 65kg bodyweight, and point estimates and 90% confidence intervals of the C(max) ratios, AUC ratios and ratios of the AUC in phase B normalised for clearance by the AUC in phase A (AUCR) were calculated. The three formulations were not bioequivalent based on the C(max) and AUC comparisons. CONCLUSIONS: The blood concentrations of hydralazine obtained with the tablet formulation tested in V-HeFT II were markedly lower than those obtained with the capsule formulation tested in V-HeFT I or the FDC ISDN/HYD single tablet used in A-HeFT. The apparently modest effect on survival observed in V-HeFT II could be explained in part by the poor hydralazine bioavailability of the tablet preparation used in this trial. ISDN exposures were similar in the two trials. The ISDN-hydralazine formulation used in V-HeFT II was not bioequivalent to the formulation used in V-HeFT I or to the FDC ISDN/HYD that had demonstrated a significant survival benefit in A-HeFT.     

Bioavailability of two new formulations of paracetamol, compared with three marketed formulations, in healthy volunteers

The aim of this study was to compare the main pharmacokinetic characteristics of two new paracetamol formulations, powder sachet and tablet, with that of three commercially available paracetamol formulations: two conventional solid tablets and one effervescent tablet. Twelve healthy volunteers participated in an open, single dose (paracetamol 1,000 mg), randomized, five-way, crossover study. Formulations studied included: formulation A: 2 x 500 mg paracetamol tablets (Laboratorios Belmac S.A.); formulation B: 1 x 1,000 mg paracetamol powder sachets (Laboratorios Belmac, S.A.); formulation C: 2 x 500 mg paracetamol film-coated tablets (Panadol, SmithKline Beecham); formulation D: 2 x 500 mg paracetamol tablets (Tylenol, McNeil); and formulation E: 1 x 1,000 mg effervescent paracetamol tablets (Efferalgan, UPSA). The primary variables were area under the plasma concentration time curve extrapolated to infinity (AUC(0-infinity)), maximum plasma concentration (Cmax), and time to maximum plasma concentration (tmax). Mean AUC(0-infinity) ranged from 52.6 (B) to 56.3 microg x h/ml (D); mean Cmax varied between 17.98 (C) and 20.73 microg/ml (E); mean tmax ranged from 0.40 (E) to 0.88 h (C); and median t(1/2) varied between 2.65 (C) and 2.81 h (A). Formulations A, B and E showed significantly shorter tmax than formulation C. The tmax and Cmax values found for formulations A and B were very similar to that found for E, an effervescent tablet formulation. In conclusion, the two new formulations of paracetamol tested in this study were absorbed rapidly after a single oral dose in healthy volunteers, similar to an effervescent paracetamol formulation and significantly faster than two ordinary commercialized paracetamol tablets.     

Bioequivalence and pharmacokinetic comparison of 3 metformin extended/sustained release tablets in healthy Indian male volunteers

This study was undertaken to compare the bioavailability and pharmacokinetic properties of 3 marketed product of metformin (CAS 1115-70-4) extended/sustained release formulation in Indian male volunteers. Study was designed as an open-label, randomized, 3-treatment, single-dose, crossover, bioavailability study comparing 3 marketed brands of 500?mg metformin extended/sustained release tablets in 18 healthy human male volunteers under fed condition. A single oral dose of 500?mg metformin sustained release products, test A (Glycomet SR), test B (Bigomet SR) and extended release reference product was administered as per computer generated randomization schedule during 3 period of the study having 7 days of washout period. A liquid Chromatography mass spectroscopy method for the determination of metformin in human plasma was developed and validated using metformin-D6 as an internal standard. A noncompartment pharmacokinetic method was employed to determine the pharmacokinetic parameters (Cmax, Tmax, AUC0-t, AUC0-∞ and t?) of metformin using WinNonlin-Node 4.0 software. Cmax, AUC0-t and AUC0-∞ were used to test for bioequivalence after log transformation of plasma data. The predetermined regulatory range of 90% CI for bioequivalence was 0.80 to 1.25. The 90% confidence intervals for log transformed data for Cmax, AUC0-t and AUC0-∞ for test A vs. reference were 82.11-98.91, 86.29-102.17 and 86.34-102.59 respectively whereas for test B vs. reference were 104.39-125.76, 94.78-112.22 and 92.85-110.33 respectively. The results of this study suggest that the test A was bioequivalent to reference product, whereas test B was not as per regulatory defined criteria.